#!/usr/bin/env bash

readonly toolName=python
readonly buildDeps=(build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev libsqlite3-dev wget libbz2-dev)
readonly buildHome="/tmp/pythonbuild"
readonly buildTgz="${buildHome}/py.tgz"

# Already defined by sequencer.sh, but may be overwritten
#readonly seq_configName="${sq_scriptName:?}.cfg"
#readonly seq_configTemplate="${seq_origin:?}/${sq_configName:?}.example"

sq_aptOpt=
sq_config=0
req_pyVersion=
sq_pyVersion=

seq_config() {
  ## or to use sequencer api with global config file:
  if ! initSeqConfig "${seq_configName:?}" "${seq_configTemplate:?}" ; then
    # End if no configuration file exists
    dry || return 1
  fi

  ## Apt cmdline option to suppress user interaction
  interactive || sq_aptOpt="-y"

  ## Disable error checks if external scripts are used
  ## e.g. error on unbound variables
  #disableErrorCheck

  ## Return of non zero value will abort the sequence
  return 0
}

step_1_info() { echo 'Status'; }
step_1_alias() { echo 'status'; }
step_1() {
  local pyPath=
  if pyPath=$(which "python${sc_pyVersion}") ; then
    info "$(python${sc_pyVersion} --version) installed"
    info -a "at ($pyPath)"
  else
    info "${toolName} version ${sc_pyVersion} not installed"
  fi
}

step_10_info() { echo 'Setup build environment'; }
step_10_alias() { echo 'buildsetup'; }
step_10() {
  exe apt update
  exe apt install "${buildDeps[@]}" ${sq_aptOpt}
}

step_11_info() { echo "(Alt)install given version"; }
step_11_options() { echo "[VERSION]"; }
step_11_alias() { echo "altinstall"; }
step_11() {
  shift
  local downUrl=
  local version="${sc_pyVersion:?}"
  [ -f "${buildTgz}" ] && return 0
  [ -n "${1:-}" ] && version="${1}"
  if ! downUrl="$(getSourceUrl "${version}")" ; then
    fatal "Could not determine download link for version ${1:-}"
  fi
  info "Downloading $sq_pyVersion from $downUrl"
  exe mkdir -p "${buildHome}"
  exe wget -O "${buildTgz}" "${downUrl}"
}

step_12() {
  local lPrefix=
  [ -z "${sq_pyVersion}" ] && getSourceUrl "${sc_pyVersion}" >>/dev/null
  exe cd "${buildHome}"
  exe tar xf "${buildTgz}"
  exe cd "Python-${sq_pyVersion}"
  if [ -n "${sc_pyPrefix}" ] ; then
    exe mkdir -p "${sc_pyPrefix}"
    endReturn "Couldn't create prefix directory ${sc_pyPrefix}"
    lPrefix="--prefix=${sc_pyPrefix}"
  fi

  exe ./configure --enable-optimizations "${lPrefix}"
}

step_13() {
  [ -z "${sq_pyVersion}" ] && getSourceUrl "${sc_pyVersion}" >>/dev/null
  exe cd "${buildHome}/Python-${sq_pyVersion}"
  # Leave one processor for other tasks
  exe make -j 3
}

step_14() {
  local lInstall="altinstall"
  [ -z "${sq_pyVersion}" ] && getSourceUrl "${sc_pyVersion}" >>/dev/null
  exe cd "${buildHome}/Python-${sq_pyVersion}"
  [ -n "${sc_pyPrefix}" ] && lInstall="install"
  exe make "${lInstall}"
}

# getSourceUrl <VERSION>
#  <VERSION>  :  can be only the major version or more specific
#
# Get the download URL for the latest .tgz file for the given version.
#
# Examples (all valid):
#   getSourceUrl 3
#   getSourceUrl 3.10
#   getSourceUrl 3.10.8
getSourceUrl() {
  [[ ${1:-} =~ ^[0-9\.]+$ ]] || return 1
  local downUrl=
  downUrl="$(curl --silent -L "https://www.python.org/downloads/source/" | \
    grep --max-count 1 -Po "href=\"\K.*Python-${1//./\\.}.*?(?=\")")"
  [[ -z "${downUrl}" ]] && return 1
  sq_pyVersion="$(grep -Po "python/\K.*?(?=/)" <<<"${downUrl}")"
  echo "${downUrl}"
}

# shellcheck disable=SC2034 # Appears unused
readonly sqr_minVersion=16
# shellcheck disable=SC1091 # Don't follow this source
. /usr/local/bin/sequencer.sh